Islands in the sun (and wind)

The idea of moving to renewable energy generation is proving attractive to many smaller communities, particularly island-based communities. Here are some of them.

Kangaroo Island: Currently powered by a 15 km undersea cable from mainland SA which is nearing the end of its design life, one option, moving the island to renewable energy generation, has been examined by UTS Institute For Sustainable Futures. The outcome of the study was that the cost of replacing the undersea cable would come in at $77 m whereas a local wind/solar/diesel hybrid system was estimated at around $87 m. However, once ongoing costs such as network charges are factored in, costs for the new cable option rise to $169 m, compared to $159 m for local supply. The system would likely include doubling the existing 8 MW diesel generation capacity, installing between four and eight wind turbines, adding five hectares of solar farm and around 800 solar rooftops. The end result would be 86% renewable and 14% diesel generation.www.bit.ly/KangUTS100

Isle of Eigg, Scotland: In 2008, the island’s electrification project was switched on, providing 24-hour power for the entire island. Previously, electricity had been provided by individual households using their own generators, resulting in excessive noise, pollution and high maintenance burdens on individuals. The project included laying of 11 km of cable and installation of three hydroelectric generators—100 kW at Laig on the west side of the island, with two smaller 5 to 6 kW hydros on the east side. Four small 6 kW wind turbines below An Sgurr and a 50 kW photovoltaic array round out the system. There are also backup generators for periods of low renewable input. To prevent overloading of the grid, each house has a maximum power draw of 5 kW, and 10 kW for businesses. When excess renewable energy is being generated, the electricity is used to heat community buildings.www.islandsgoinggreen.org

Bruny Island, Tasmania: As looked at in ReNew 136, the CONSORT Bruny Island Battery Trial is an ARENA-funded project to install up to 40 battery systems on the island, with the view to stabilising the grid and reducing the use of diesel generation during the peak season. Households that participate in the trial will be provided with a large subsidy to install solar power and a smart battery storage system. They will also be able to sell their stored energy into the electricity market via Reposit Power. So far, the first round of participants have been selected. www.brunybatterytrial.org

Rottnest Island: The Rottnest Island Water and Renewable Energy Nexus project involves the construction of a 600 kW solar farm to complement the existing 600 kW wind turbine, which was installed in 2005 and already produces around 30% of the island’s electricity needs, saving more than 300,000 litres of diesel a year. The solar farm is expected to push the renewables portion to 45%, further reducing the need for diesel fuel. Funding for the project will be jointly provided by the Rottnest Island Authority ($2 m) and ARENA, which will provide $4 m. www.bit.ly/RottnestSust

King Island: The King Island Renewable Energy Integration Project (KIREIP) aims to increase the island’s renewable energy generation to around 65%, and up to 100% at times, while reducing the reliance on diesel fuel. By adding energy storage and energy flow control, the system allows greater contribution of power from renewable sources. Integration of smart grid technology provides the ability to control customer demand to match the available renewable energy supplies. The storage system, the largest electrochemical battery ever installed in Australia, is capable of producing 3 MW of power and storing 1.6 MWh of usable energy.www.kingislandrenewableenergy.com.au

Island of Ta’u: The island of Ta’u in American Samoa lies around 6400 km off the west coast of the USA. Until recently it was entirely diesel-powered, with diesel being delivered by ship. Disruptions to deliveries had at times resulted in severe electricity restrictions—not great when you rely on electric pumps for basic water requirements. Ta’u now has a solar power and battery microgrid that can supply nearly 100% of the island’s electricity requirements from renewable energy. The new microgrid has all but eliminated power outages and greatly reduced the cost of providing electricity to Ta’u’s almost 600 residents. The system consists of a healthy 1.4 MW of solar generation capacity from SolarCity, which feeds into 6 MWh of grid-grade storage from Tesla (Tesla recently aquired SolarCity) consisting of 60 Tesla Powerpacks. The project was funded by the American Samoa Economic Development Authority, the US Environmental Protection Agency, and the US Department of Interior. It is expected to offset more than 400,000 litres of diesel per year.blog.solarcity.com/island-in-the-sun